Method of constructing an earthen dike and combination trenching and back-filling machine therefor



METHOD 0F CONSTRUC Filed July 12, 19 3 R. SENSIBAR ET AL 3,331,209 TING AN EARTHEN DIKE AND COMBINATION TRENCHING AND BACK-FILLING MACHINE THEREFOR 7 Sheets-Sheet 1 I INVIENTORS, JACOB R.SE NS\BAR.. AgNQLD E. sTKus Jul fls, 1967 J. R. SENSIBAR ETAL 3,331,209 METHOD Of" CONSTHUCTINC AN EARTHEN )EKE AND COMBINATION FILLING MACHINE THEREFOR 'IHENCHINQ AND BACK Filed July 12, 195;. 7

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3,331,209 INATION OR J. SENSIBAR ET AL July 18, 1967 METHOD OF CONSTRUC NG AN EARTHEN mm AND cows 7 1 TRENCHING AND BACK-FILLING MACHINE THEREF Filed July 12, 1963 '7 Sheets-Sheet 4 A N LD E. PETKUS Filed July 12, 196

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' METHOD OF CONSTRUCTINC' AN EAR'I'HEN DIKL AND COMBINATION TRHNCHI-NG AND BACK'F'ILLING MACHINE THEREFOR 7 Sheets-Sheet 5 INVENWJRS JACOB R. SENSJBAR ANOLD E..PETKUS July 18,1967 J R. SENSlBAR-ETAL 3,331,209

METHOD OF CONSTRLfCTING AN EARTHEN DIKB AND COMBINATION T RENCHING AND BACK-FILLING MACHINE'THEREFOR Filed July 12, .1965 7 Sheets-Sheet 6 INVENTORSI .JACOB R. SENS\BAR g NoLb E. PETKUS 3,331,209 NATION J. R. SENSIBAR ETAL METHOD OF CONS'I'RUCTINC- AN BARTHEN DIKE AND COMBI July 18, 1967 TRENCHING AND BACK FILLING MACHINE THEREFOR 1963 '7 Sheets-Sheet '7 Filed July 12,

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R MA /M United States Patent O 3,331,209 METHOD OF CONSTRUCTING AN EARTHEN DIKE AND COMBINATION TRENCHING AND BACK-FILLING MACHINE THEREFOR Jacob R. Sensibar and Arnold E. Petkus, Chicago, Ill., assignors to Construction Aggregates Corporation, Chicago, Ill., a corporation of Delaware Filed July 12, 1963, Ser. No. 294,604 14 Claims. (Cl. 61-31) This inventoin relates generally to trenching and backfilling machines and more particularly to a combination trenching and backfilling machine having improvements which render the same particularly efiicacious for the practice of a novel method for building earthen dikes or the like.

Machines for excavating or digging a furrow or trench in the earth are of course well known and have assumed a variety of different forms. Similarly, there have heretofore been provided trenching machines for use With other devices whereby a trench could be dug and then at least partially filled with another material or object, such as tile, concrete, electrical cable, etc. However, the erection of massive structures such as earthen dikes presents problems with which the known forms of trenching and backfilling machines are unable to cope.

In its simplest forms, a dike comprises a mound-like wall which projects above the surface of a body of water, and its function may vary from that of -a levee for flood prevention to a wall for segregating a portion of the body of water so that said portion may then be drained off or evaporated. Where cost is no object and it is intended that the dike be a permanent structure, then permanent materials such as concrete or metals may be employed in the construction thereof. However, it is well known that most dikes are relatively massive and temporary structures which are generally built as a prerequisite for the carrying out of some other operation, such as draining a walled oif area to permit construction or mining thereon. Accordingly, most dikes of necessity are built in the least expensive manner possible, namely, by using ordinary earth which is an abundantly plentiful raw material.

Unfortunately, a dike made only of earth is porous and thus permits water to seep therethrough. It thus becomes necessary for the dike to be made impervious as for example with a center or core of some impervious material which prevents seepage of water therethrough. Consistent with the problem of maintaining low costs, impervious cores for earthen dikes may be made from another readily available material, clay.

' Using conventional methods, heretofore a typical earthen dike was built in the fololwing manner. A relatively small pile of clay was first placed in the position where it was intended to erect the center core of the dike. Porous earth was then built up on either side of the small pile of clay. Additional clay was then piled atop the original clay and more earth then built up therearound. The described process was repeated as often as was necessary to produce a dike of the desired height and thickness. Those versed in the art will immediately recognize the excessive time, labor, equipment and expense involved in the conventional dike building process, particularly in situations where the body of water is relatively deep and the length of the dike long enough to be measured in terms of miles. Quite obviously, then, it would be desirable if the dike could be built up to its full section first by simply piling the earth and then inserting the center core therein.

It is therefore an important object of this invention to provide an improved combination trenching and backfilling machine which enables earthen dikes to be built in a new and more efficient manner. With the subject inven- 3,331,209 Patented July 18, 1967 tion, an earthen dike may be built by inserting a center core into an earthen wall which has already been built up to its desired section.

In building earthen dikes, it is frequently desirable or even essential that the center core material be poured or filled in two distinct layers rather than in a solid mass of one material. Thus, for example, it may be desired that the core comprise a bottom layer of wet or plastic clay and a top layer of dry clay.

It is therefore another important object of the invention to afford an improved trenching and backfilling machine having means for pouring two distinct layers of different materials in the backfilling operation. A related object is to alford such a machine having means for adjusting the depth of the layers of core material as desired.

Another object is to provide an improved trenching and backfilling machine of the character described having excavating means which create a minimum of disturbance in the surrounding dike material and in the adjacent bed material. This is especially important where the foundation or bed material is crystalline or composed of similar frangible material such as crystalline salt. In this regard, the machine employs an excavating screw or auger.

A further object is to aiford an improved trenching and backfilling machine of the character described having means for firmly packing the backfill material into place. With this object in view, the invention employs a novel oscillating consolidator in addition to the customary tremie chute or tube.

Still another object is to provide an improved trenching and backfilling machine of the character described having means for adjusting the operational depth of the excavating auger as required. Thus, for example, the center core may be filled to a depth below the bed of the water body to further insure against water seepage and to firmly anchor the dike.

Yet another object is to afford an improved trenching and backfilling machine of the character described, having means for automatically lubricating the tremie chute to insure free flow of the core material thereover.

Still a further object is to provide an improved trenching and backfilling machine of the character described having means for utilizing the excavated earth by returning and adding the same to the thickness of the dike.

Yet a further object is to afford an improved trenching and backfilling machine of the character described having jet water-boring means for aiding in the lowering of the auger and tremie into operational position.

Another object is to provide an improved trenching and backfilling machine of the character described having hydraulic means for conditioning the earth being excavated and simultaneously creating an overpressure to insure against a sucking or pumping eifect by the auger of the backfilled core material.

Still another object is to afford an improved trenching and backfilling machine of the character described having hydraulically operated locomotion motors in addition to the previously described hydraulic systems, the water for said hydraulic systems being drawn from the surrounding body of water in which the dike is being built.

With the foregoing and other object-s in view which will appear as the description proceeds, the invention consists of certain novel features of construction, arrangement and a combination of parts hereinafter fully described, illustrated in the accompanying drawings, and particularly pointed out in the appended claims, it being understood that various changes in the form, proportion, size and minor details of the structure may be made without departing from the spirit of sacrificing any of the advantages of the invention.

For the purpose of facilitating an understanding of our invention, we have illustrated in the accompanying drawings a preferred embodiment thereof, from an inspection of which, when considered in connection with the following description, our invention, its mode of construction, assembly and operation, and many of its advantages should be readily understood and appreciated.

Referring to the drawings in which the same characters of reference are employed to indicate corresponding or similar parts throughout the several figures of the drawings:

FIG. 1 is a pictorial perspective view showing the machine of the invention in operation on a dike, with portions of the dike being broken away to show the operational positioning of the auger and associated tremie therein;

FIG. 2 is a side elevational view of the machine with the auger positioned so that only a portion thereof extends below the top surface of the dike;

Fig. 3 is an enlarged sectional view of the auger and associated tremie structure taken substantialy on the plane of line 33 in FIG. 2 and viewed in the direction indicated;

FIG. 4 is a fragmentary sectional view taken substantially on the plane of broken line 4-4 in FIG. 3 and viewed in the direction indicated;

FIG. 5 is a sectional view taken on the plane of line 5-5 in FIG. 4 and viewed in the direction indicated;

FIG. 6 is a fragmentary rear elevational view of the tremie structure and illustrating constructional details of the lower consolidator;

FIG. 7 is an enlarged fragmentary side elevational view showing the relationship of the raising and lowering means for the auger-tremie structure;

FIG. 8 is a fragmentary perspective view of the bottom of the auger-tremie structure showing the hydraulic jet means; and

FIG. 9 is a schematic flow diagram showing the operation of the machine to excavate a trench and simultaneously backfill the same with two layers of different backfill materials.

Referring now more particularly to FIGS. 1 and 2 of the drawings, it will be seen that the reference numeral 10 indicates generally a combination trenching and backfilling machine embodying the principles of the invention. The machine 10 comprises a main frame 12 having a deck 14 which may extend the full length thereof. A suitable canopy or roof 16 may be mounted on the forward portion of the deck 14 to provide a sheltered area in which may be positioned the various controls, power generators, and the like. The main frame 12 may be mounted for locomotion on pairs of front and rear caterpillar-type crawlers, 18 and 20 respectively.

The hopper 22 is mounted on the frame 12 and through a suitable opening formed therein. Associated with the hopper 22 may be a bangboard such as 24 for preventing damage to the remainder of the machine during the loading of a backfilling or coring material into the hopper. A second and smaller frame 26 is connected to the rear of the main frame 12 and is adapted to be towed thereby. Mounted on the second frame 26 is a second hopper 28 which discharges onto a materials conveyor such as 30. The conveyor 30 projects forwardly and terminates at a point within the main frame 12 for reasons which will become apparent as the description proceeds.

As will subsequently be more fully described, the machine 10 utilizes water and hydraulic motors for numerous of its functions, including the operation of the crawlers 18 and 20 at a constant pre-determined rate of forward speed. For this purpose, a pair of large intake pipes 32, 32, project outwardly from the main frame beyond the side of the dike D, and are adapted to have their mounts operationally positioned within the body of water W surrounding said dike. The intake pipes 22 communicate with a large multi-sectioned feed pipe 34, said feed pipe being in turn connected to a hydraulic pumping and manifold complex indicated generally by the numeral '35. The pumping and manifold complex 35 is mounted on a second deck or platform 36 which is adapted to move vertically in a manner which will subsequently be described. It is important to note at this point, however, that the feed pipe 34 is provided with a number of swivel joints such as 38 thereby permitting the pipe to follow the vertical movement of the complex and platform 36 (see, for example, FIGS. 1 and 2).

The platform 36 is mounted atop a novel elongated excavator-tremie structure 40 which is slidably mounted for vertical movement on the main frame 12. The structure 40 comprises an angular framework having a pair of side plates 42, 42, interconnected by suitable cross members such as 44 and 46 (see FIG. 3). Each of the side plates 42 is provided with a longitudinal recess 48 extending over substantially the full length thereof and adapted to slidably receive therein pairs of rollers such as 50, 5 mounted on both sides of the frame 12.

Raising and lowering cables 52 and 54 are likewise positioned to extend within the recesses 48 and are connected to suitable anchoring means such as 56 and 58 adjacent the opposite ends of the recesses (see FIG. 7). The cables 52 and 54 are threaded over pairs of sheaves 60, 60, and 62, 62, mounted in the frame 12, whereby the position of the cables is converted into a substantially horizontal relationship as indicated. The free ends of cables 52 and 54 are then connected, by means of adjustable tensioning means 64, 64, to a horizontally oriented sprocket wheel 66 positioned forwardly in the machine, It will thus be appreciated that motion of the raising cable 52 to the right as viewed in FIG. 9 will cause the lowering cable 54 to play out and move toward the left, thereby raising the structure 40. Reversal of the cable motions will of course result in lowering the structure 40.

Referring now to FIG. 3 of the drawings, it will be seen that the forward area (right-hand side as viewed in the drawings) between the side plates 42 is closed by an arcuate partition wall 68 which may be semi-circular in cross-section as indicated and semi-cylindrical in elevation. Rotatably journalled within the area defined by the partition wall 68 is an excavating member comprising a screw or auger 70. Suitable drive means 72 are rovided at the top of the structure 40 for rotating the auger 70, and a shoe member 74 having suitable auger-bearing means is provided at the bottom of the structure 40, as shown in FIG. 4.

It will be noted that the auger 70 (and the structure 40) is mounted at an angle of approximately 60 with the horizontal. It has been determined that this is the most efficient cutting and excavating angle for such a device. In situations involving a foundation composed of sensitive brittle layers of crystalline salts (viz., the bottom of the Dead Sea in Israel) the cutting angle being substantially parallel to the planes of the salt layers insures against fracturing said foundation. It will thus be appreciated that as the machine is moved forwardly by the crawlers 18 and 20, the blades of the auger 70 will cut a trench in the dike D and convey the excavated material upwardly in the well known manner. When the upwardly conveyed material reaches an area of no further constraint, such as at the termination of the auger enclosure 76 (see FIG. 4), this material of course falls off of the auger by the force of gravity. A conveyor 78 (see FIGS. 1 and 2) is connected to the frame 12 and is adapted to catch and transport such falling material. As indicated in FIG. 1, the conveyor 78 projects outwardly beyond the side of the dike D so that the excavated material therefrom is deposited on the side of the dike thereby contributing to building the same up; at least the width thereof.

Other known forms of cutting and excavating means may likewise be employed, although the auger is preferred particularly in the building of dikes. This preference results from the fact that the trenches are frequently dug in frangible crystalline salt or salt-permeated soil, and the auger creates a minimum of disturbance in the surrounding soil.

Positioned in the rearward area between the side plates 42 (left-hand side as viewed in FIG. 3) is a generally semicylindrical tremie chute 80 opening in a direction opposite to that of semi-cylindrical wall 68. The tremie chute 80 is positioned to receive the coring material discharging from the first hopper 22, and said material thus slides down the chute and into the trench which has been excavated by the auger 70. A Water pipe 82 is connected to the pumping complex 35 and runs down the center of the chute 80. The pipe 82 is provided with numerous discharge outlets along the length thereof and thus serves to lubricate the wall surface of the chute 80 with water. Such lubrication is desirable to insure free flow of the coring material thereover, particularly where the material comprises a plastic somewhat adhesive mass, such as wet clay.

For purposes of insuring efiicien-t consolidation of the coring material as it flows into the trench, the chute 80 is provided with a separate solidable section 84 at the bottom thereof which may conveniently be referred to as the lower consolidator. As indicated in FIGS. 4 and 7 of the drawings, the lower consolidator 84 includes a pair of medially positioned agitator blades 86, 86, which project beyond the horizontal extremity of the chute 80. A pair of long flexible drive pipes 88, 88, are connected to the top of the lower consolidator 84. The drive pipes 88 are freely positioned adjacent the side extremities of the chute 80, and are connected at the top thereof to drive means indicated generally by the numeral 90 (see FIGS. 3 and 4). The drive means 90 may include an eccentric 92 adapted to create linear motion in a pair of pivoted arms 94 attached thereto. The drive pipes 88 are in turn connected to the arms 94. It will thus be appreciated that movement of the arms 94 causes the lower consolidator 84 to oscillate in a plane of motion parallel to the chute 80, thereby insuring efficient consolidation of the coring material in the trench.

As already indicated hereinabove, it is frequently desirable in building dikes, to backfill the trench with distince layers of two different materials. Thus, for example, while the material in the hopper 22 which makes up the bottom layer of the core may comprise plastic or wet clay, the top layer or remainder of the core may comprise dry clay. To this end, the tremie chute 80 is provided with a pair of opposed longitudinal channels 96, 96 (see FIGS. 3 and 5), extending over substantially the full length thereof. Slidably and adjustably positioned in the channels 96 is a washboard-like upper consolidator 98 which spans the full width of the chute 80, but is considerably shorter in length (see FIG. 4). The marginal edges of the upper consolidator 98 are connected to a pair of driving beams 100, 100, slidably positioned in the channels 96 and which are in turn connected to the pivot arms 94. It will thus be appreciated that motion of the pivot arms 94 oscillates the upper consolidator 98 in a manner similar to the oscillation of the lower consolidator 84.

Referring particularly to the flow diagram of FIG. 9, the function of the upper consolidator may now be fully appreciated. It will thus be seen that the wet clay flows down the tremie chute 80 as described and forms the bottom layer of the dike core. Simultaneously, the dry clay from the second hopper 28 is dropped by the conveyor 30 onto the upper consolidator 98. The constant forward movement of the entire machine 10 causes the bottom edge of the upper consolidator to act as a wiper of the bottom core layer, and the dry clay being discharged from said consolidator thus forms a distinct top core layer. It will thus be appreciated that the upper consolidator 98 functions as a strike-off plate between the wet and dry clays,

6 and it will likewise be appreciated that the relative depths of the bottom and top core layers may be readily controlled by simply adjusting the vertical position of the upper consolidator on the tremie chute.

The initial lowering of the full length of the structure 40 into operational position beneath the top surface of the dike is normally a difficult operation unless some suitable excavating or other means is first done. Furthermore, it is desirable that the auger 70 not be in operation during such initial lowering. To overcome these initial lowering difliculties, there is provided at the bottom of the structure 40 hydraulic jet means indicated generally at 102 (see FIG. 8). The jet means 102 comprises an H-like pipe structure including a pair of pipes 104, 104, secured to the side plates 42 and a connecting pipe 106 secured to the cross member 44. Mounted in the pipes 104 and 106 are a plurality of jet nozzles 108. Water is supplied from the pumping complex 35 to the jet means 102 under high pressure through a feed pipe 110. The described jet means are employed during the initial lowering operation and serve to excavate or blast away the dike soil sufficiently so that said operation is easily accomplished. The jet means may, of course, be turned off once the auger has reached operational position.

Those skilled in the art will of course appreciate that the side plates 42 of the structure 40 function additionally to prevent cave-in of any particular section of the trench before the same has been completely filled with the core. It will also be appreciated that the auger 70 exerts a sucking or pumping action which might have a tendency to suck the back-filled wet clay around the side plates 42 toward the auger. To eliminate this possibility, there are provided four water pipes 112 from the complex 35 which direct water at spaced points onto the auger (see FIGS. 3 and 4). This water creates an overpressure which insures against the described pumping action, and likewise affords means for cleaning off debris which might become entangled or clogged on the auger. Moreover, this water serves to condition the dike soil being attacked by the auger, thereby facilitating the excavation operation.

When it is desired to merely transport the machine over the ground, the entire structure 40 is of course raised above ground level in the manner already described. To this end, there is likewise provided a system of hydraulic jacks 114 adjacent the rear of the frame 12 for further elevating the bottom of the structure 40 in rough or uneven terrain. The jacks 114 additionally function to level the machine 10' during all phases of its operation and transport.

From the foregoing description and drawings, it should be apparent that we have provided a novel combination trenching and backfilling machine having numerous improvements and refinements and which is particularly well suited for dike building. The machine enables dikes to be built by a :more efficient method then heretofore possible, namely, by inserting an impervious core into an earthen V dike which has previously been built up to full section.

The machine permits the core to be formed in two layers from different materials, and the entire operation is automatic. Moreover, the machine operates almost exclusively on hydraulic motors utilizing water pumped in from the surrounding body of water.

It is believed that our invention, its mode of construction and assembly, and many of its advantages should be readily understood from the foregoing without further description, and it should also be manifest that while a preferred embodiment of the invention has been shown and described for illustrative purposes, the structural details are nevertheless capable of wide variation within the purview of our invention as defined in the appended claims.

What we claim and desire to secure by Letters Patent of the United States is:

I. A combination trenching and backfilling machine comprising a frame, locomotion means associated with said frame, an elongated excavator-tremie structure mounted in said frame, excavating means mounted forwardly in said structure and adapted to dig a trench as said frame is moved forward, a first chute positioned in said structure to the rear of said excavating means, a second chute positioned in said structure to the rear of said first chute and having a bottom terminal leveling edge higher than the bottom discharge portion of said first chute, a first supply means and a second supply means depositing a first and second backfill material re:- spectively in said first and second chutes, said chutes depositing said first and second materials simultaneously as said trench is being dug whereby said first backfill material forms the bottom layer within said trench and said second backfill material forms the top layer therein, means for adjusting the vertical position of said leveling edge relative to the position of said first chute whereby the relative depth of the layers of said first and second backfill material into the trench may be readily controlled.

2. A combination trenching and backfilling machine comprising:

a frame;

locomotion means associated with the frame to cause the same to move;

excavating means adapted to dig a trench as said frame is moved;

a tremie chute positioned to the rear of said excavating means;

supply means cooperating with said tremie chute to deposit a backfill material therein;

a consolidator plate slidably mount-ed on said chute and extending to the bottom thereof; and

drive means for vertically oscillating said consolidator plate.

3. The machine of claim 2 in which a second consolidator plate is adjustably mounted rearwardly in said structure and in vertically spaced relationship with said first consolidator plate, and drive means for vertically oscillating said second consolidator plate.

4. The machine of claim 3 in which said supply means comprises a hopper mounted on said frame, a second hopper associated with said frame and adapted to cooperate with said second consolidator plate to deposit a second backfill material thereon whereby said trench is automatically filled with a bottom layer of said first backfill material and a top layer of said second backfill material.

5. A method of erecting earthen dikes comprising the steps of piling earth up to substantially desired dike size, excavating a longitudinal trench through said earth partially backfilling said trench with a bottom layer of spreadable substantially water impervious material; leveling the top surface of said bottom layer at a depth below the top of the trench while controlling said depth of said bottom layer and the quantity of said bottom layer of material backfilled into said trench and simultaneously backfilling said trench with a second layer of substantially water impervious material over said first leveled layer of material, said second material being different than said first material.

6. The method of claim 5 in which said bottom layer is wet clay and said second layer is dry clay.

7. A combination trenching and backfilling machine comprising an elongated frame, locomotion means associated with said frame, an elongated angular excavatortremie structure slidably mounted in said frame and capable of vertical movement therein, said structure including a pair of spaced side plates and front and rear substantially semi-cylindrical partition walls therebetween affording a pair of longitudinal chambers opening to the front and rear of said structure, an excavating auger rotatably journalled in said front chamber, a first hopper for a first backfill material mounted on said frame and adapted to discharge said first backfill material onto said rear partition wall, a lower consolidator plate slidably mounted on said rear partition wall and extending to the bottom thereof, flexible linking means connected to said lower consolidator plate, drive means connected to said linking means for vertically oscillating said lower consolidator plate, and elevator means on said frame for selectively :moving said structure between an inoperative position where the same is entirely above ground to an operative position where the same is substantially completely beneath the ground.

8. The machine of claim 7 in which a second hopper for a second backfill material is connected to said frame, an upper consolidator plate connected between said side plates in vertically spaced relation with said rear partition wall and said lower consolidator plate, linking means con- -:nected to said upper consolidator plate and drive means for vertically oscillating said upper consolidator plate, and conveyor means cooperating with said second hopper for discharging said second backfill material onto said upper consolidator plate.

9. The machine of claim 8 in which means is provided for adjusting the vertical position of said upper consolidator plate whereby the relative depth of the layers of said first and second backfill materials backfilled into the trench excavated by said auger may be readily controlled.

10. The machine of claim 7 in which said flexible linking means comprises a pair of flexible pipes extending longitudinally along said rear partition wall.

11. The machine of claim 7 in which a plurality of water pipes project at vertically spaced intervals into said front chamber, said pipes adapted to direct water onto said auger during the operation thereof.

12. The machine of claim 7 in which water supply means is positioned in said rear longitudinal chamber, said water supply means adapted to lubricate said rear partition wall and lower consolidator to facilitate the flow of said first backfill material thereover.

13. The machine of claim 7 in which high pressure hydraulic jet means is positioned in said structure adjacent the bottom thereof, said jet means adapted to excavate the ground for initially lowering said structure into operational position.

14. The machine of claim 7 in which hydraulic jack means is associated with said frame for automatically maintaining said machine level during operation thereof and further raising said structure above ground level when the same is in inoperative position.

References Cited UNITED STATES PATENTS 494,368 3/1893 Decker 37-81 1,164,072 12/1915 Crall 6163 2,040,022 5/1936' Philips 6130 2,048,710 7/1936 Ranney 61-63 2,757,514 8/1956 Wyatt 7131 2,797,503 7/ 1957 Livingston 617 X 2,885,861 5/1959 Jackson 61-63 2,994,974 8/ 1961 Domenighetti 378l FOREIGN PATENTS 792,799 10/ 1935 France.

OTHER REFERENCES Engineering News-Record, Jan. 19, 1939, pp. 63 and 64. (Copy in Group 421; class 61, subclass 3.)

EARL I. WITMER, Primary Examiner. 

1. A COMBINATION TRENCHING AND BACKFILLING MACHINE COMPRISING A FRAME, LOCOMOTION MEANS ASSOCIATED WITH SAID FRAME, AN ELONGATED EXCAVATOR-TREMIE STRUCTURE MOUNTED IN SAID FRAME, EXCAVATING MEANS MOUNTED FORWARDLY IN SAID STRUCTURE AND ADAPTED TO DIG A TRENCH AS SAID FRAME IS MOVED FORWARD, A FIRST CHUTE POSITIONED IN SAID STRUCTURE TO THE REAR OF SAID EXCAVATING MEANS, A SECOND CHUTE POSITIONED IN SAID STRUCTURE TO THE REAR OF SAID FIRST CHUTE AND HAVING A BOTTOM TERMINAL LEVELING EDGE HIGHER THAN THE BOTTOM DISCHARGE PORTION OF SAID FIRST CHUTE, A FIRST SUPPLY MEANS AND A SECOND SUPPLY MEANS DEPOSITING A FIRST AND SECOND BACKFILL MATERIAL RESPECTIVELY IN SAID FIRST AND SECOND CHUTES, SAID CHUTES DEPOSITING SAID FIRST AND SECOND MATERIALS SIMULTANEOUSLY AS SAID TRENCH IS BEING DUG WHEREBY SAID FIRST BACKFILL MATERIAL FORMS THE BOTTOM LAYER WITHIN SAID TRENCH AND SAID SECOND BACKFILL MATERIAL FORMS THE TOP LAYER THEREIN, MEANS FOR ADJUSTING THE VERTICAL POSITION OF SAID LEVELING EDGE RELATIVE TO THE POSITION OF SAID FIRST CHUTE WHEREBY THE RELATIVE DEPTH OF THE LAYERS OF SAID FIRST AND SECOND BACKFILL MATERIAL INTO THE TRENCH MAY BE READILY CONTROLLED. 